Crimping is extensively used for joining two pieces of metal or other ductile materials by deforming one or both pieces. For example, in the automotive industry, the crimping technique has replaced soldering to a large extent. In an exemplary crimping process a stripped wire is inserted in correctly sized crimping vanes of a terminal, and a crimping tool or a crimping die is used to tightly squeeze the crimping vanes of the terminal against the wire. In order to fulfil predetermined requirements for a crimped product, the terminal, the crimping material, for example the stripped wire, and a crimping tool have to be tailored to each other. For this purpose, crimping tools or crimping dies have specific crimp profiles adapted to specific terminals and crimping materials.
European Patent Application EP 1503454 A1 describes a typical crimping process for joining a contact terminal to a respective electrical wire for generating wire harnesses used in vehicles. U.S. Patent Application Publication 2005/0050940 A1 describes an example of a crimping tool as it is applied in automated mass production.
As already mentioned, the crimping die has to deform in a defined manner at least one of the two components to be combined in the joining process, typically the terminal. This means that usually the material of the crimping tool has to be harder than the material of both the materials to be joined. In order to increase the lifetime of the crimping die, these tools preferably have an exchangeable or changeable crimping die insert of hard material, preferably a hard metal or a hard metal alloy. Nevertheless, exchangeable crimping die inserts wear off rapidly during thousands or hundreds of thousands of crimping processes performed by a crimping die or crimp tool designed for mass production. Hence, the crimping die insert is a wearing part. The usage of the crimping tool for many joining processes gradually changes the crimp profile of the crimping die insert. This may lead to the result that the crimped product does no longer meet predetermined requirements with respect to the reliability and/or durability. Therefore, it is necessary to periodically replace the crimping die insert, i.e. after having performed a predetermined number of crimps.
To optimize the lifetime of a crimping die insert, it would be beneficial that a crimping die insert has more than one identical crimp profile. For example, in case a crimping die insert has two identical crimp profiles, the lifetime of the crimping die would double. The German patent application DE 4427306 A1 describes an exchangeable contour insert for an automated strand placement machine, wherein the exchangeable contour insert includes two identical crimp profiles arranged on the top and bottom face of the contour insert.
However, the two identical crimp profiles of DE 4427306 A1 are integrated in an exchangeable contour insert carry the risk that one of the crimp profiles is excessively used, whereas the other one is hardly used. This may occur, since it is difficult to determine the degree of wear and tear of several identical crimp profiles of an exchangeable crimping die insert. In particular, it is not possible to reliably identify the condition of a crimp profile with the naked eye, so that it is not readily possible to identify whether a crimp profile has already been used or not. For this purpose, it is either necessary to steadily control the quality of the crimped product and/or to apply expensive measurement tools to periodically investigate the crimp profiles of the crimping die inset in a time-consuming process.
The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions.